Multiple-input-multiple-output (MIMO) wireless communication systems concurrently transmit information using more than one spatial channel. Some of these communication systems use multiple subcarriers (i.e., tones) and modulate subsymbols on the subcarriers. These systems may transmit simultaneously using multiple antennas with each antenna transmitting using the same subcarriers.
During propagation to the receiver, the subsymbols carried on each subcarrier and spatial channel are generally distorted by background noise and cross-talk, among other things. Cross-talk may refer to the distorting influence that a particular subsymbol transmitted on a particular subcarrier and spatial channel has upon another subsymbol carried on the same subcarrier of another spatial channel. Separating the transmitted spatial data streams and removing the effects of cross-talk and noise at the receiver is a complex process and is very processing intensive.
Thus there are general needs for separating spatial data streams and removing the effects of cross-talk and noise at the receiver with reduced complexity and a reduced number of operations.